1. Field of the Invention
The present invention relates to a device for closing a hose by pinching it.
More precisely, the invention relates to a mechanical device enabling a flexible tube or hose to be closed completely by pinching in order to interrupt the flow of a liquid, the tube or hose being, in particular, of the type used in the field of medicine for administering medication or other similar agents to patients by perfusion.
2. Description of the Related Art
Devices are already known in the medical field enabling such a hose to be closed by longitudinally displacing a piece which includes a rectilinear slot that terminates at one of its ends in a circular recess. When the hose is located in the circular recess, normal liquid flow takes place, whereas when the piece is moved in linear translation, the slot pinches the hose, thereby interrupting the flow of liquid. However, in such systems, the hose is not closed in very reliable manner since there is a risk of the wall of the hose deforming or kinking, thereby enabling a residual flow to be maintained along the hose, and that is unacceptable.
Such a device for closing a hose by pinching is usable in the medical field, in particular with a peristaltic pump for causing a liquid to flow under pressure from a liquid storage bag to a perfusion line. Such peristaltic pumps are of small size and it is therefore advantageous for the closure device itself to be small in size and adapted to the structure of such a peristaltic pump.
Prior art closure devices, in particular those described in U.S. Pat. Nos. 5,437,635 and 5,290,239, not only fail to provide good closure of the flow of liquid along the hose, but in addition they are not adapted to use in association with an ambulatory peristaltic pump of small size.
Peristaltic pumps are well known in this field.
Such peristaltic pumps are described in particular in patent application WO-95/31643 published on Nov. 23, 1995 in the name of the Applicant. Such pump devices are essentially constituted by a pump module proper, or xe2x80x9ccassettexe2x80x9d, which contains presser wheels co-operating with a deformable tubular element that can be removably inserted in a motor unit, the motor unit enabling the presser wheels to be rotated and thus enabling the peristaltic pump to operate. In which case, it will be understood that when the motor stops and the pump proper is extracted from the case of the motor, the pump wheels no longer perform their function of providing local sealing of the tube element, and that liquid can thus flow under gravity through the pump and along the associated tube. In this particular case, it is therefore essential to provide, in association with the peristaltic pump, a mechanical device for closing the tube in order to avoid any accident due to misoperation of the cassette, whether by hospital staff or by the patient.
The present invention provides a device that closes a hose by pinching, particularly but not exclusively a device associated with a peristaltic pump to enable the flow to be interrupted effectively and completely while preferably being compatible with the peristaltic pump.
According to the invention, a device for closing a hose by pinching, where the zone of the hose that is to be closed has an axis XXxe2x80x2, the device being characterized in that it comprises:
a moving closure piece having a slot in the form of a circular arc of radius R, said slot having a first end and a second end, said second end being connected to a recess of dimensions that are not less than the dimensions of the right section of the hose, said slot having in the vicinity of its first end a width that is suitable for pinching said hose completely, the second end of the slot having a width that flares to connect with said recess;
means for defining a fixed axis of rotation YYxe2x80x2 that is substantially parallel to said axis XXxe2x80x2 of the hose;
means for guiding said closure piece in rotation about said axis of rotation in such a manner that said slot moves generally along a circle of radius equal to the radius R, centered on said axis of rotation, and disposed in a plane orthogonal to said axis of rotation; and
means for rotating said closure piece between a first position in which the hose passes freely through said recess of the closure piece and a second position in which said hose is pinched in the first end of said slot.
It will be understood that because of the circular displacement of the closure piece which includes a closure slot that is itself circular, effective and complete closure of the hose is obtained by displacement of the closure slot in a circular movement.
Preferably, the device further comprises fixed means for holding said hose substantially stationary in the displacement direction of said closure piece. Also preferably, the device comprises means for locking said closure piece in its second position.
In a preferred embodiment, the device for closing the outlet hose from a peristaltic pump which comprises a housing, a first cylindrical nozzle for connection to an inlet hose, and a second nozzle for connection to said outlet hose, said nozzles having axes that are substantially parallel, is characterized in that it comprises a first assembly mounted in fixed manner on said second nozzle to define said holding means, said locking means, and a portion of said means for providing guidance in rotation, and a second assembly pivotally mounted about said first nozzle to define said arm, said closure piece, a portion of the means for providing guidance in rotation, and the means for displacing said closure piece in rotation.
It will be understood that in this particular application, the embodiment of the closure device is particularly well adapted for use with a peristaltic pump, since the device is reduced to no more than two parts that are very simple, using one of the nozzles of the peristaltic pump as a fixing member for one of the parts of the closure device and the other nozzle of the peristaltic pump as a pivot axis for the moving second aspart of the closure device.